1. Field of the Invention
The invention relates to an image forming apparatus, and particularly to an image forming apparatus which uses a recording material on one side of which an image has been formed.
2. Related Background Art
In recent years, the senses to environmental problems have been growing on the part of the users of image forming apparatuses. So, from the viewpoint of the saving of natural resources, reusable recording materials having an image formed on one side thereof, but having any image not yet formed on the other side thereof are extensively used. The reusable recording material having an image formed on one side thereof, but having an image not yet formed on the other side thereof will hereinafter be referred to as the backing sheet.
Here, when the image formed on one side includes confidential information, the confidential information may leak out. As a method of preventing the leakage of such confidential information, there is a method of forming a solid image (visible image) on the image-formed side of the backing sheet to thereby paint out a text or image of high confidentiality and make it indecipherable. This method is to set the backing sheet on a sheet supplying cassette (containing portion), and form a solid image on the image-formed side thereof by the user's manual operation. The backing sheet on which the solid image has been formed is discharged onto and stacked on a sheet discharging tray.
According to this method, however, the backing sheet having the solid image formed on the image-formed side thereof and stacked on the sheet discharging tray need be moved from the sheet discharging tray to the sheet supplying cassette by the user for the purpose of forming an image on a side of the backing paper on which any image is not yet formed. Here, there has arisen the problem that the user must do the cumbersome work of moving the backing sheet from the sheet discharging tray to the sheet supplying cassette.